const fp = require('lodash/fp')
const _ = require('lodash')

//数据
// horsepower  马力， dollar_value  价格，in—stock  库存
const cars = [
  {
    name: 'Ferrari FF', horsepower: 660,
    dollar_value: 700000, in_stock: true
  },
  {
    name: 'Spyker C12 Zagato',
    horsepower: 650, dollar_value: 648000,
    in_stock: false
  },
  {
    name: 'Jaguar XKR-S', horsepower:
      550, dollar_value: 132000, in_stock:
      false
  },
  {
    name: 'Audi R8', horsepower: 525,
    dollar_value: 114200, in_stock: false
  },
  {
    name: 'Aston Martin One-77 ',
    horsepower: 750, dollar_value: 1850000,
    in_stock: true
  },
  {
    name: 'Pagani Huayra', horsepower:
      700, dollar_value: 1300000, in_stock:
      false
  },
]


// let isLastInStock = function (cars) {
//   //获取最后一条数据
//   let last_car = fp.last(cars)
//   console.log(last_car)
  
//   //获取最后一条数据的 in_stock 属性值
//   return fp.prop('in_stock', last_car)
// }

// 练习1
// let isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last)
// console.log(isLastInStock(cars))

// 练习2
// let firstName = fp.flowRight(fp.prop('name'), fp.first)
// console.log(firstName(cars))

// 练习3
let _average = function (xs) {
  return fp.reduce(fp.add, 0, xs) / xs.length
}

// let averageDollarValue = function (cars) {
//   let dollar_values = fp.map(function(car) {
//     return car.dollar_value
//   }, cars)
//   return _average(dollar_values)
// }

// let averageDollarValue = fp.flowRight(_average, fp.map(car => car.dollar_value))
// console.log(averageDollarValue(cars))

// 练习4
let _underscore = fp.replace(/\W+/g, '_')
const sanitizeNames = fp.flowRight(_underscore, fp.lowerFirst)

console.log(sanitizeNames('Hello World'))